Quantifying the effects of the soil erosion factors on water-eroded slopes

The factors influencing soil erosion are diverse and complex. However, a comprehensive comparative analysis of the various factors remains insufficient. By collecting, selecting and summarizing related studies across China, this study established a comprehensive dataset that includes runoff depth (R) and soil loss (SL) under various soil erosion factors (soil order, land use, vegetation coverage, slope length, slope gradient, and precipitation), to identify erosion pattern in different runoff plots based on rainfall events. Results showed that the average runoff depth (WR) and weighted average soil loss (WSL) of observed water erosion events in China are 20.10 mm and 331.92 t/km2, respectively. Semi-alfisols, amorphic soils, and pedocals reveal significantly higher R and SL. Forests prove most effective in mitigating soil and water loss, whereas grasslands and bare land exhibit similar runoff levels. Vegetation coverage of 40-60 % notably reduces both R and SL. R and SL fluctuate with the increase in slope length and slope gradient, but increase with growing precipitation. When the slope length exceeds 15 m and the gradient surpasses 25 degrees, R and SL decrease significantly. Precipitation is the most significant factor impacting both R (contributing 58.70 %) and SL (contributing 30.25 %). This study underscores interactions among erosion factors and proposes multivariate linear regression models to predict R and SL based on these variables. It also contributes to clarifying the effects of erosion factors on slopes, providing a scientific basis for soil erosion modeling and control.